2001 Ford Taurus wagon DOHC Brake Booster

Hello, guys, the sound of hissing air is coming from the area of the power brake booster. The hissing modulates when I press or release the brake pedal and I don’t think it really ever stops, if I press and hold the brake pedal and then turn engine off booster immediately loses vacuum and pedal rises back up. Though I still do get brake assist while driving. I figure the leak is either inside the unit or the check valve on the top front of the booster has gone bad/is stuck open. I have a few questions: 1) can I just reach in with some kind of pliers and yank the check valve out? Or would that just break the valve? 2) If I do end up having to replace the brake booster, will I have to remove the wiper arms, windshield  cowl, wiper transmission/linkage, and lower drainage tray and drainpipe? Haynes guide not really clear on some of this. Any guidance appreciated! Thanks, Pop

Yes, you can just pull the check the valve out of the grommet that seats it in the booster.
Yes, you will have to remove all that of that stuff to get to the booster to change it.

Hey pop! If you do decide to replace the booster, consider replacing the master cylinder, too. They like to leak brake fluid at the rear seal and contaminate the brake booster.

When replacing the booster, I usually remove the air filter box, master cylinder, cruise actuator (position aside), throttle body, transmission cable bracket and the two master cylinder lines. That'll get you enough room to ease the booster out. Cowl removal would certainly help but is not necessary, IMO. 

Thanks guys! Looks like the booster definitely needs to come out. Good idea on the master cylinder. Was thinking it might be good to go ahead and replace it. Right now I have everything out through the transmission cable bracket. -Pop

The cowl and tray definitely did have to come out. And yes, I am replacing the master cylinder. Part is on order! Should be in later today. I really appreciate all the guidance! Thanks guys!

Good man Pop

Put car together enough to test brakes. Started engine, pressed pedal, and it seems firm enough, but the weird thing is now I cannot get the car out of Park. Shift lever will not move. Shift cable, whose bracket I did have to move out of the way to get booster out, does not seem bound up or jammed. I am pretty sure I pit the brake pedal back together correctly. But I guess I could be wrong, so I’ve attached a picture. I have tried moving the shift lever with the linkage connected at transmission as well as unconnected. Can’t figure out what I have done wrong. Any ideas appreciated! UPDATE: My brake lights do not illuminate when I press brake pedal. So I am guessing I did not reinstall pedal switch correctly, maybe that has something to do with it?

ANOTHER UPDATE: Did some additional research and I know now I definitely reinstalled switch wrong. I am reinstalling brake switch correctly and will give it another try. 

 

Definitely going to be a problem with the brake pedal position switch. A little difficult to tell from the picture if it's installed correctly, but the wires don't exactly look like they are laying naturally, like they may have gotten twisted. And is that tape? Maybe bad news under that tape...

Reinstalled the brake light switch, and brake lights work again and can shift out of park and into all gears. Yes I think that is tape, it appears someone has been in here before. Thanks, guys, car is back on the road! YOU ROCK!!!